Descriptions on general polymetal gates or metal gates can be found, for example, in Japanese Patent Laid-Open No. Sho 60(1985)-89943, Japanese Patent Laid-Open No. Sho 61(1986)-150236, Japanese Patent Laid-Open No. Sho 60(1985)-72229, Japanese Patent Laid-Open No. Sho 59(1984)-10271, Japanese Patent Laid-Open No. Sho 56(1981)-107552, Japanese Patent Laid-Open No. Sho 61(1986)-127123, Japanese Patent Laid-Open No. Sho 61(1986)-127124, Japanese Patent Laid-Open No. Sho 60(1985)-123060, Japanese Patent Laid-Open No. Sho 61(1986)-152076, Japanese Patent Laid-Open No. Sho 61(1986)-267365, Japanese Patent Laid-Open No. Hei 1(1989)-94657, Japanese Patent Laid-Open No. Hei 8(1996)-264531, Japanese Patent Laid-Open No. Hei 3(1991)-119763, Japanese Patent Laid-Open No. Hei 7(1995)-94716, U.S. Patent Official Gazette, that is, U.S. Pat. No. 4,505,028, U.S. Pat. No. 5,719,410, U.S. Pat. No. 5,387,540, IEEE Transaction Electron devices, Vol. 43, No. 11, November 1996, Akasaka et al, p. 1864-1869, Elsevier, Applied Surface Science 117/118 (1997) 312-316, Nakajima et al, and Nakajima et al, Advanced metalization conference, Japan Session, Tokyo Univ. (1995).
With regards to oxynitriding treatment, descriptions can be found in U.S. Pat. No. 4,282,270, while descriptions on hydrogen exhaust gas treatment can be found in U.S. Pat. No. 5,202,096, U.S. Pat. No. 5,088,314, Japanese Patent Laid-Open No. Hei 8(1996)-83772, and Japanese Patent Laid-Open No. Hei 9(1997)-75651.
With regards to the problems of water content and oxidation, there are descriptions, for example, in Japanese Patent Laid-Open No. Hei 7(1995)-321102, Japanese Patent Laid-Open No. Sho 60(1985)-107840 and U.S. Pat. No. 5,693,578.
With regards to synthesis of water using a catalyst, there are descriptions, for example, in Japanese Patent Laid-Open No. Hei 6(1994)-333918, Japanese Patent Laid-Open No. Hei 6(1994)-115903, Japanese Patent Laid-Open No. Hei 5(1993)-152282, Japanese Patent Laid-Open No. Hei 6(1994)-163871, Japanese Patent Laid-Open No. Hei 5(1993)-141871, Japanese Patent Laid-Open No. Hei 5(1993)-144804, Japanese Patent Laid-Open No. Hei 6(1994)-120206, Nakamura et al, Proceedings of the 45th Symposium on Semiconductors and Integrated circuit Technology, Tokyo Dec. 1-2, 1993, the Electronic materials committee, p. 128-133.